Been Having This Congested Feeling For A While, On Top

Been having this congested feeling for a while, on top of that feeling every now and then I often cough up phlegm. I don't even have to hock it up. I just feel it in my throat and cough it out. I have been taking Zyrtec but that doesn't seem to be helping at all. I'm not sure if its allergies or sinus, or another infection.